PC Steve Higgs of Blackpool Police said: "It would appear from the way that these thieves have broken into the zoo that this was a planned and pre-meditated crime and that the offenders knew what they were looking for and knew that the monkeys would be in enclosures."

The zoo's director, Darren Webster, said: "We are extremely saddened by the theft of these monkeys and it is imperative they receive the correct care in order to survive.

"All the animals were born here at Blackpool Zoo and are part of our zoo family, so I would urge anyone with any information to contact the police."